1. Field of Invention
Aspects of the present invention relate to ore fines agglomerate to be used in a sintering process, the agglomerate comprising a diameter between 0.01 mm and 8.0 mm, produced from natural ore fines and sodium silicate as main agglomerant and at low temperature curing. Aspects of this invention also relate to a process of production of ore fines agglomerates to be used in sintering processes.
2. Description of Related Art
Several technologies of cold ore agglomeration are known by the prior art. These technologies are based on the agglomeration of ore fines using basically, cements, mortars, organic agglomerants and carbonated residues as agglomerant agents. In these acknowledged agglomeration processes, the fines used need to undergo a milling stage so that it may feature adequate granulometry for the agglomeration, being that this unit operation requires appropriate equipment and energy.
Besides that, several additives, associated to these agglomerants, are added in order to accelerate the cure of agglomerates and improve its mechanical properties. The use of several agglomerants and additives, in addition to make the dosage system more complex, it also hampers the reduction of operational cost and the agglomerate quality control.
Other technologies for residues agglomeration known by the prior art and used in the steel mill and metallurgy industry use the sodium silicate, among other additives, to accelerate the curing process of the agglomerates, however, in this case, the obtained agglomerates present diameters above 12 mm and are used as metallic load for reduction reactors.
Additionally, most of these processes use briquetting as unit transformation operation, that is, the fines used in these processes also require to undergo a conformation stage so that it may display an adequate granulometry for the agglomeration.
Therefore, in general, the agglomerates obtained from these processes known by the prior art present the need of high dosage of agglomerants (above 10%) and high time for the curing of the product (more than ten days for curing time). Furthermore, the traditionally used agglomerants are expensive and represent more than 70% of the operational cost of transformation of the fines in agglomerates, resulting in high production costs.
Further, the agglomerates resulting from these processes present low resistance to water contact, high generation of fines during transportation and handling (low mechanical resistance) and high generation of fines due to thermal shock inside the reduction reactors. Most of the times, the agglomerated product presents contamination by elements that are deleterious to the operation of metallurgic reactors, besides the high transformation cost. The low resistance to water contact refers to the fact that these agglomerants are not completely insoluble and its fragility to thermal shock may be related to the chemical and physical stability of the agglomerant.
Production process of agglomerates to be used in sintering process, with diameter between 0.01 mm and 8.0 mm, produced from ore natural fines and sodium silicate as main agglomerant, and curing at low temperature, is not mentioned in the prior art.